Modification and analysis of load follow control without boron adjustment for CPR1000

• The multiple model applies to a wide range power regulating process.
• CPR1000 adopts the boron adjustment free control mode with its previous structure.
• The load follow capability can be extended to EOL by the analyzed control parameters.

As the nuclear power percentage increases gradually, it brings more attention to advanced reactor designs, performance and flexibility, including enhanced load follow capability. CPR1000, the main reactor type of China national development, employs a new control mode to perform the load follow operation in this paper, which is different from the traditional mode in current generation plants and replaces the frequent manipulation of soluble boron concentration during daily maneuvers with control banks movements, thereby reducing the amount of waste water generated during the cycle and greatly simplifying the design of the chemical volume and control system. A dynamic multiple model of the ten-node core is built, considering the neutron coupling effect and mutual influence from the neighboring nodes. The control banks are regrouped to realize the reactivity/temperature control by mechanical automatic control banks (M banks) and the power distribution control by axial offset control banks (AO bank). Simulation results show that so long as the optimum control parameters are selected, this boron adjustment free control method can provide the capability till the end of life for CPR1000 reactor core to follow a daily load curve.